London called and the United States answered during the first week of the 2014 Championships at Wimbledon, as a mix of established stars and up-and-coming talent provided early thrills at the All England Club. Twelve American players registered at least one win in the main singles draws, a number matched by only the Czech Republic.

Ninth-seeded John Isner was particularly strong on the men’s side in reaching the third round, first beating British wild card Daniel Smethurst, 7-5, 6-3, 6-4, followed by a 32-ace performance against Finland’s Jarkko Nieminen, 7-6, 7-6, 7-5. Impressively, Isner did not have his serve broken in either match. A tough four-set loss to Spain’s Feliciano Lopez saw the first three sets go to tiebreaks, further cementing the 29-year-old’s reputation as a marathon man at Wimbledon.

Isner’s Davis Cup teammate Sam Querrey also acquitted himself well as he attempts to make his way back into the Top 50, beating fellow American Bradley Klahn and then taking two-time Wimbledon semifinalist Jo-Wilfried Tsonga to the limit in a 4-6, 7-6, 7-6, 6-3, 14-12 loss.

Alison Riske was also among the six Americans to reach the third round in singles. For the 23-year-old Pittsburgh product, it’s now 10 wins in five Grand Slam appearances since last year’s Wimbledon after victories over No. 26 Anastasia Pavlyuchenkova of Russia and Camila Giorgi of Italy. Elsewhere, 2013 US Open standout Victoria Duval, 18, advanced past the qualifying tournament and proceeded to knock out No. 29 seed Sorana Cirstea in the first round of the main draw; 19-year-old Madison Keys upset No. 31 Klara Koukalova en route to the third round; CoCo Vandeweghe, 22, toppled No. 27 seed Garbine Muguruza; and Lauren Davis, 20, upended No. 12 Flavia Pennetta in the second round.

Here are more headlines from Wimbledon during Week 1:

Serena stunned again: Off of a stinging Roland Garros defeat in the second round a month ago, top-ranked Serena Williams once more had her hopes for an 18th Grand Slam title squashed, this time by 24-year-old Frenchwoman Alize Cornet. In a match delayed by the rain, Cornet rallied from a set down to defeat Williams, 1-6, 6-3, 6-4, in the third round.

“I cannot believe it,” said Cornet on defeating the reigning US Open champion. “A few years ago, I couldn’t play on grass, but now I have beaten the world No. 1. It’s the biggest upset of the tournament. A dream. I cannot believe I did it myself."

Williams appeared primed to capture her sixth Wimbledon title, easily dispatching fellow American Anna Tatishvili and South African Chanelle Scheepers in the first two rounds. She looked just as solid in winning the first set off Cornet before the Frenchwoman deftly switched tactics and employed more drop shots, getting Williams to chase a growing number of returns in vain in sets two and three.

The 32-year-old remains the reigning US Open champion. That said, she now has been beaten before the quarterfinals at four of the past five majors. The 2014 US Open will also be the first time Williams attempts to defend an Open crown without at least winning one other Grand Slam event since 2000.

"I don't really know what I did wrong," said Williams after the loss. "Usually I do. Usually I know I did this, this, and that."

Venus Valiant: Both Williams sisters lost in the third round, but 34-year-old Venus that will likely fly back to the United States feeling that her game is rounding into form.

The five-time Wimbledon champion evenly battled 2011 ladies’ winner and No. 6 seed Petra Kvitova in what was arguably the best match of Week 1. Each player won more than 100 points in the match and broke the other's serve only once, with Kvitova ultimately claiming victory, 5-7, 7-6, 7-5. After the two-and-a-half hour contest, International Tennis Hall of Famer Billie Jean King tweeted praise: "Congrats to @Petra_Kvitova and @Venuseswilliams on raising the bar."

Kvitova tried to fight pressure with pressure: "On every point I was really trying," said Kvitova. "I knew that to break her, I had to fight on every point. I was lucky in the end." The 24-year-old Czech had 34 unforced errors but also 48 winners to go along with 11 aces. Williams had six aces and 25 winners against 19 unforced errors.

“It's a shame there had to be a loser in this match and more of a shame that it had to be me," said Williams. "But all I can say is that it's great to see women's tennis on such a high level. I always expect a great match when I play her. You look at our score lines and they're never easy. She manages to somehow bring her best tennis against me."

Both sisters will remain in England for a while longer, as they remain alive in the Wimbledon ladies’ doubles draw.

Bob, Mike and the fortnight: Bob and Mike Bryan will try to make this a summer most memorable, starting with their gentlemen’s doubles title defense at Wimbledon. A fourth Wimbledon crown would be title number 99, leaving them one shy of the century mark. They then would have a greater opportunity to clinch the career milestone on American soil, having committed to play at the Citi Open in Washington D.C., the Western & Southern Open in Cincinnati and the US Open in New York.

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For more coverage of Americans at the 2014 Wimbledon Championships, please also read: